In order to improve the thermal decomposition performance of AP in solid propellants, CuO/Al composite catalyst was prepared by sol-gel method, and its morphology and structure were characterized by SEM, XRD and other means. The catalytic effect of the catalyst on the thermal decomposition of AP was investigated by DSC method.Results show that the CuO/Al composite catalyst structure is complete, and the catalytic effect of composite catalyst CuO/Al on AP is obviously better than that of mixture catalyst CuO/Al. The catalytic effects of CuO/Al composite catalysts with different mass fractions of 1%, 3% and 5% were compared. It was found that the low temperature decomposition peak and high temperature decomposition peak decreased by 24.2℃ and 120.2℃, respectively, when the addition amount was 5%.The results show that the prepared CuO/Al composite catalyst can significantly reduce the thermal decomposition temperature of AP and improve its thermal decomposition performance.